THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.

[18:00:05]

WOLF BLITZER, CNN ANCHOR: Happening now: divide and conquer. The GOP front-runner is firing back at his rivals and their new dealing to deny him the nomination. We are standing by to hear live from Donald Trump.

Desperation? Trump says Ted Cruz and John Kasich are showing signs of weakness by joining forces to deprive him of delegates. Will their strategy work?

The long short list. Hillary Clinton reportedly eying potential running mates, even as she keeps wrong to lock up the Democratic nomination. Are any of her V.P. prospects surprising?

And dangerous mission. Additional U.S. forces are being ordered to fight ISIS. Will it lead to even more American troops on the ground in Syria and at risk?

We want to welcome viewers in the United States and around the world. I'm Wolf Blitzer. You're in THE SITUATION ROOM.

Tonight, Donald Trump is blasting an unprecedented alliance between his opponents, Ted Cruz and John Kasich, calling it pathetic and an act of collusion. We standing by to hear more from Donald Trump. He holds a rally in Pennsylvania son on this, the eve of the new round of crucial primaries that Trump is likely to sweep.

Cruz says he and Kasich are coordinating strategy in upcoming contests to try to stop Trump from winning the GOP nomination. Cruz will focus in on next week's Indiana primary, while Kasich concentrates on Oregon and New Mexico hoping to peel delegates away from Trump. Trump's rivals say they are driven by fear the GOP front-runner would lose to Hillary Clinton in the fall.

But Trump says they're simply desperate.

Our correspondents and analysts are all standing by as we cover all of the news that's breaking right now.

Up first, let's go to our senior White House correspondent, Jim Acosta. He's covering Trump's swing through Pennsylvania. Jim, is the Trump camp at all worried about this new Cruz-Kasich

Donald Trump is dismissing the deal cut by Ted Cruz and John Kasich as an act of desperation. But talk to the stop Trump forces, and they're looking at the numbers, and arguing this actually alliance might work.

(BEGIN VIDEOTAPE)

ACOSTA (voice-over): On the new political marriage of convenience formed by his two remaining rivals to stop his campaign, Donald Trump accused Ted Cruz and John Kasich of being divorced from reality.

DONALD TRUMP (R), PRESIDENTIAL CANDIDATE: It shows that they are just getting killed.

ACOSTA: Leading in all the polls to sweep in the next round of states up for grabs tomorrow, Trump now smells blood, tweeting about the Cruz-Kasich deal as proof. "They are unable to beat me on their own, so they have to team up in a two-on-one." And then hammering the duo again in Rhode Island.

TRUMP: If you collude in business or if you collude in the stock market, they put you in jail. But in politics, because it's a rigged system, because it's a corrupt enterprise, it shows how weak they are, it shows how pathetic they are.

ACOSTA: But Cruz says Trump is sounding off for good reason.

SEN. TED CRUZ (R-TX), PRESIDENTIAL CANDIDATE: Oh, listen, I don't doubt that Donald Trump is going to scream and yell and curse and insult and probably cry and whine some as well. That has been Donald's pattern.

ACOSTA: Arguing the name of the game is denying Trump the magic number of delegates needed to clinch the nomination, Cruz and Kasich are now dividing up the map, with the Texas senator focusing solely on upcoming Indiana, where he's stronger, while yielding New Mexico and Oregon to the Ohio governor, territory better suiting him.

CRUZ: We decided to allocate our time and energy and resources on the state of Indiana. Governor Kasich decided to allocate his resources elsewhere. I think that made sense from both campaigns.

ACOSTA: The polls indicate Cruz could borrow enough votes from Kasich to deny Trump a victory in Indiana, siphoning delegates away from the real estate tycoon.

GOV. JOHN KASICH (R-OH), PRESIDENTIAL CANDIDATE: Is it colluding? No. Collude, what does that even mean?

ACOSTA: Kasich pushed back on the notion that he's on the ropes.

KASICH: No. I'm not desperate. Are you? Are you desperate? Because I'm not.

ACOSTA: But he also seemed to spin his end of the deal with Cruz just a touch, saying voters can support the candidate of their choice.

KASICH: I'm not going to go tell anybody how to vote. They can -- but, look, this is a matter of resources. And, you know, we are running a national campaign and we want to apply our resources where we think they can be used most effectively.

TRUMP: But I said to myself that's pretty bad. That's pretty bad.

ACOSTA: But the alliance seems to have emboldened Trump, who's come up with new insults for Kasich.

KASICH: I have got eggs and fruit and I wanted bacon.

TRUMP: This guy takes a pancake and he is shoving it in his mouth. It's disgusting. Do you want that for your president? I don't think so.

(END VIDEOTAPE)

[18:05:02]

ACOSTA: Now, as for Kasich's eating habits, and who ever thought we would be talking about that during the course of a campaign, the Kasich campaign fired back at Trump, saying, "We were looking for some Trump Steaks for the governor, but no one seems to sell them anymore," so a dig at Donald Trump and those old Trump Steaks he used to sell.

Insults aside, a top official with the never Trump movement said this plan worked up by Kasich and Cruz is long overdue. They wish this had happened weeks ago, adding it could actually stop the front-runner.

I did talk to a Trump adviser who said, yes, this deal could hurt Donald Trump in Indiana, but they feel like it won't halt their march to the magic number of 1,237 delegates. Wolf, Indiana or no Indiana, they feel like they're on the way to becoming the nominee -- Wolf.

BLITZER: Jim Acosta, thanks very much.

Also tonight, there's evidence Ted Cruz may think his anti-Trump alliance with John Kasich could be successful.

Our political reporter, Sara Murray, is joining us right now.

Cruz, what, he is vetting a potential running mate. What are you hearing?

Ted Cruz is maybe feeling confident, maybe he just feels this is the prudent move. But the national chairman for his campaign confirmed to CNN earlier today that Ted Cruz is going through the vetting process and that Carly Fiorina is on that short list. Now, of course Carly Fiorina would be an interesting choice. She's

proven to be very critical of Hillary Clinton, very critical of Donald Trump, and also was once a rival to the candidates who are still in the race. So it will be interesting to see.

Obviously, a short list means there are more candidates on there than just Carly Fiorina, and Ted Cruz is still trailing Donald Trump, so he may never get a chance to unveil that V.P. pick, Wolf.

BLITZER: Sara, looks like Donald Trump could have a pretty good day tomorrow, the five Republican presidential primaries. What are you hearing?

MURRAY: That's right, Wolf. We are here in Pennsylvania, where Donald Trump will make his closing argument before voters here go to the polls. This is one of a number of states in what we're calling the Acela primary here along the East Coast.

These are states where Donald Trump is positioned to do very well, potentially even sweep all of the states for victory. Interestingly, the Trump campaign even feels confident right here in Pennsylvania. This is a state where a number of the delegates will be unbound, but the campaign has released an official slate, and they're trying to prove they're more organized, more disciplined in the delegate hunt, particularly when it comes to unbound delegates in states like this than they had been in previous contests, Wolf.

BLITZER: Thanks very much, Sara Murray reporting for us from Wilkes- Barre. Donald Trump getting ready to speak before that big crowd over there. We will have more coverage. That's coming up.

We are also standing by to speak with Katrina Pierson, the national spokesperson for the Trump campaign. Stand by, and we will speak with her shortly.

GLORIA BORGER, CNN SENIOR POLITICAL ANALYST: Look, I think it is kind of a last ditch effort. You have been calling it a Hail Mary. I think it is a Hail Mary.

I think Cruz figures out he has to do something. Their only shot is at a second ballot at the convention. That's what they're working towards. I was talking to Paul Manafort today, who is the delegate hunter for Donald Trump, and here's what he said about the agreement.

He said: "I think the agreement is a sign of desperation. The Washington insiders will always put their interests ahead of what voters want."

In a way, Wolf, it does play into the whole Trump narrative that it is the insiders who are trying to get him, trying to rig the system against him. By the way, what's the guarantee that all those Kasich voters are going to suddenly turn around and vote for Cruz? I don't think so.

KEVIN MADDEN, CNN CONTRIBUTOR: This is a strategy of last resort, and this is obviously not the way that they -- this is not a strategy they're choosing. It is a strategy that's chosen them.

This was -- their focus all along was to try and get as many delegates as possible so that they would eventually be the nominee. Now that that's not the case, they were trying to get one of the other campaigns to drop out. Ted Cruz just probably 30, 60 days ago was arguing Kasich should clear the field for him. Now this is one of the cases where if they're going to stay in, they have to work together.

The only thing that matters right now is getting to Cleveland, making sure that Cleveland is an open or a contested convention, and that all candidates at that stage are then created equal. That's not likely to be the case. I think the thumb will be on the scale for Donald Trump, given that he has won more delegates. But this is their last strategy.

BLITZER: I want everybody to stand by.

Katrina Pierson is joining us on the phone right now. She's the national spokeswoman for the Trump campaign.

Katrina, thanks very much.

Your reaction to the deal between Kasich and Cruz? They're teaming up to prevent Donald Trump from getting to the magic number, 1,237, on the first round of voting. He says he is happy about it, Trump, but privately he can't be very thrilled about it.

[18:10:05]

KATRINA PIERSON, TRUMP CAMPAIGN SPOKESPERSON: You know, Wolf, I have to say it is interesting, because they have admitted one thing in doing this, and that is the fact that Donald Trump is the only candidate that can reach 1,237 prior to a convention.

And just a week ago, both of them were saying, oh, it is not going to happen, Trump can't get there. Senator Cruz went as far as to say nobody is going to get there. But what they have admitted today is that in fact Donald Trump can get there, and this attempt to try and really at this point stop the will of the voters is very much desperation between two campaigns who are institutional candidates, propped up by special interests, who have never had a clear message or a message that was resoundingly rejected from the voters.

Senator Cruz is trailing Donald Trump two-and-a-half million votes, and Kasich is trailing five-and-a-half million votes. The voters are not going to fall for this kind of manipulation, because I think it is safe to say today that Cruz and Kasich are no longer even running against Donald Trump. They're running against the voters in the Republican Party.

BLITZER: But, Katrina, they can't get the 1,237 they need to get the nomination on the first ballot. They themselves acknowledge that, but they can prevent Trump from reaching that number.

And if you have to go to round two, a lot of pledged delegates become unpledged, if you will, and everyone suggests Trump could be toast at that point. Your reaction?

We have heard this mantra since the beginning of the campaign, as politicians dropped out of the race and that the support would consolidate around someone else, and it hasn't happened. Donald Trump has picked up voters, not to mention the last national FOX News poll had Senator Cruz drop 10 points in the last month. Both of these candidates are running third in one of the elections coming up.

I just don't think that it is possible, but it is showing a sign of desperation because you have two candidates that were put in office by the establishment now wanting to protect the establishment, lets everyone know that Donald Trump is the anti-establishment candidate.

BLITZER: All the polls suggest Trump will do well tomorrow, but a week from tomorrow, that's Indiana. What happens if it is just Trump and Cruz in Indiana, Kasich is dropping out of Indiana he says for all practical purposes, and Cruz beats Trump in Indiana? What does that say?

PIERSON: I don't suspect that Cruz is going to beat Donald Trump in Indiana. The polls still have Mr. Trump leading at least by five or six points at this point in time.

But I do have to think that I don't think voters in Indiana are going to buy this type of nonsense. Yes, they do want a fight, but if you have to gang up in order to win and they won't even win at this point, then that says something else about you, particularly when you have millions of voters who have chosen Donald Trump to lead the fight against Hillary Clinton.

People in Indiana care about jobs, they care about getting control of illegal immigration, they care about taxation. When you are talking about Senator Cruz and his support for TPA, which gives rise to NAFTA on steroids, and the Trans-Pacific Partnership, the voters in Indiana, they are wising up. A lot of people are wising up.

As I just mentioned, the last month, Senator Ted Cruz has dropped 10 points in national polls, and that's astounding.

BLITZER: The argument they make, both Kasich and Cruz, is that Trump, if he were the Republican nominee, it would be a disaster for the Republicans. He couldn't beat Hillary Clinton, they say, he would lose decisively and other Republicans, down-ballot Republicans would be slaughtered, if you will.

They take a look at his negatives out there nationally. Your reaction to that argument that they make, why they have to prevent him from being the Republican nominee?

PIERSON: Well, a lot of these suits and geniuses on the GOP would love to tell everybody two cycles ago, it has to be John McCain. John McCain can win. Guess what, he didn't.

They did it again with Romney. Oh, Mitt Romney can win, it will be a landslide. And guess what, he didn't. Now these same people with their magical crystal ball are trying to tell us Donald Trump can't win, when he has been the one candidate that has been able to consolidate the party, that has brought in new voters, that does have crossover appeal, and puts states in play that no other candidate could do.

I'm not concerned about what the establishment consultants and D.C. pundits are thinking and saying. The only thing that matters is what the American public wants. And right now they want a political outsider, someone that can go to Washington, D.C., put the lobbyists on the back burner, and put the American family first.

There's only one candidate in this race on both sides that would do that, and that's Donald J. Trump.

BLITZER: A lot of focus on Trump's demeanor out there on the campaign trail. He is really ridiculing John Kasich's eating habits. He says, "I have never seen a human being eat in such a disgusting fashion."

[18:15:05]

Why does he need to do that?

PIERSON: Well, again, these rallies of Mr. Trump with his supporters, and it's just -- they're all like friends. He loves them, they love him, and they joke around and have a good time at the rallies. He has always been that way.

Mr. Trump is more serious when it comes to interviews or even giving speeches, and we are going to see another one of those next week, Wolf.

BLITZER: Another one of what next week?

PIERSON: Actually, this week.

BLITZER: This week on Wednesday, he is delivering a foreign policy speech, carefully crafted. That's the speech where he's going to be reading it from a teleprompter, right?

PIERSON: It is going to be a prepared speech. We are really excited about it. And that's where you're going to see Donald Trump talk about what no one else talks about, and that's actually how to solve problems that we have cross the world. BLITZER: This will only be the second teleprompter speech, we're

told. He did it at the AIPAC meeting, the American Israel Public Affairs Committee meeting, when he spoke about Israel and the Middle East. This is a foreign policy speech that he will read from a teleprompter, but you're saying there will be more down the road in weeks to come. Is that right?

PIERSON: Absolutely.

Mr. Trump wants to give a series of speeches, so just so he can make clear that everyone understands what his policies are and why he has the vision that he has for this country and its future, so that we don't have to deal with the media filter and the campaign that pulls his words out of context.

We're really excited and we're happy that he is ready to get out there and start putting forth his vision to go up against Hillary Clinton and win in November.

BLITZER: Because he always makes fun of the other candidates for -- especially Hillary Clinton for reading speeches from a teleprompter. But what you're saying is when it comes to substantive policy speeches, foreign policy, domestic policy, we will see more of him reading a teleprompter than we have in the past. Is that right?

PIERSON: Yes, you will definitely see more prepared speeches. It is interesting that you have career politicians, people that have been in politics pretty much their lives, decades, who still can't give a substantive speech without a teleprompter.

Donald Trump speaks from the heart. He put all of his policies out there from the heart. But they keep getting picked apart by the media and pulled out of context. And now it is time to make sure we leave no stone unturned, so that he can put out his vision without a media filter or a campaign parsing his words.

BLITZER: And the word is that Megyn Kelly, the FOX News anchor, has secured an interview with Donald Trump, is that right, for her special she's doing on FOX, the FOX broadcasting network?

PIERSON: I can't actually confirm that right now, Wolf, but I will definitely look into that for you.

BLITZER: Look into that and you will get back to us.

Katrina Pierson, thanks very much for joining us.

PIERSON: Great to be here. Thank you.

BLITZER: Katrina Pierson is the national spokesperson for the Trump campaign.

John Kasich, by the way, he will talk about his new deal with Ted Cruz right here on CNN. He will join Anderson Cooper later tonight "A.C. 360" 8:00 p.m. Eastern.

Much more coming into THE SITUATION ROOM now. We will take a quick break. We will be right back.

(COMMERCIAL BREAK)

[18:22:22]

BLITZER: Tonight, Donald Trump is hurling some insults at both Ted Cruz and John Kasich for a new reason.

His two remaining opponents have teamed up to try to take him down. As we stand by for a new Trump event in Wilkes-Barre, Pennsylvania, let's get back to our political team.

David Chalian, Dana Bash reported, what, about a month or so ago that there was effort under way for these two guys to team up against Trump. Didn't happen then. What changed?

DAVID CHALIAN, CNN POLITICAL DIRECTOR: Remember, even before that, seven-and-a-half weeks ago, Mitt Romney gave that scathing speech in which he suggested a strategy like this to split the map. That's when Marco Rubio was still in the race.

But clearly what happened was is that Ted Cruz got mathematically eliminated from becoming the nominee. That's what happened here. The Cruz folks felt they had reason now to engage in a deal with Kasich. But, Wolf, this is about one thing and one thing only right now, and it's next Tuesday, the state of Indiana.

That's what this deal is about. Cruz needed a one-on-one shot with Trump. He's going to get that because of this deal in Indiana. Of course, Kasich will still be on the ballot. This was the way by announcing this deal to signal to everyone outside spending money on this race how to position their dollars.

(CROSSTALK)

BLITZER: So, Cruz is going all in on Indiana. If Cruz loses Indiana, he walks away? Is that what I'm hearing?

(CROSSTALK)

CHALIAN: I don't know that he will walk away. I doubt that highly, because I think there's still going to be a fervent strain inside the Republican Party that's going to be opposed to Trump that Cruz will be able to tap, but if he loses Indiana after doing this, I think the oxygen comes out, the wind of the sails just dissipates.

BORGER: This isn't the first time in American history that campaigns have made deals with each other about coordinating, but the difference now is that the campaigns are not allowed to talk to their super PACs and say where to spend their money, as David is talking about.

They actually have to make an announcement about it, so they can signal to their super PACs, don't spend your spend there. Spend your money somewhere else.

MADDEN: Here is one of the big challenges that they face too, is that this is a very inferior message to ask your voters to vote against somebody rather than for them.

Donald Trump has a much better message in that sense. The other thing is, Cruz and Kasich supporters, these aren't natural allies. Both of them look at each other as emblematic of the reason that we have this party split right now. And, lastly, it is very late to try to convince voters to engage in tactical voting.

BLITZER: Because I suspect some of those voters let's say in Indiana who like Kasich, they would rather have Trump than Cruz.

MADDEN: Right. They're much more this sort of blue-collar, Midwestern, Rust Belt voter that has more of a claim I think with a Donald Trump and Kasich than they would Cruz.

(CROSSTALK)

[18:25:00]

BLITZER: If Kasich walks away, some of them would say, you know what? I am going with Trump. It could backfire.

TRUMP: You look at Kasich, I don't think he knows what -- did you see him? He has the news conference all the time when he is eating. I have never seen a human being eat in such a disgusting fashion.

I'm always telling my young son Barron, I'm saying -- and I always do with my kids, all of them. I would say, children, small, little bites. Small. This guy takes a pancake and he's shoving it in his mouth. It's disgusting. Do you want that for your president? I don't think so.

(END VIDEO CLIP)

BLITZER: Your reaction when you saw that, Jeffrey?

JEFFREY TOOBIN, CNN SENIOR LEGAL ANALYST: Donald Trump has very refined ideas about what's disgusting. Those of us who have followed his career for a long time, one of the reasons I never thought he would run for president is he had to shake hands so often.

He has a real aversion to germs. He doesn't like to shake hands with people. You notice he signs memorabilia, but he doesn't shake hands the way most politicians do. You remember when Hillary Clinton went to the bathroom during a debate, he went on about how that was disgusting.

I guess we can get used to a lot of judgments from Donald Trump about what's disgusting, and we're going to be hearing a lot more. BLITZER: Kasich responded to Trump's comments.

He tweeted this. This is Kasich tweeting. "Donald Trump, we were looking for Trump Steaks for the governor, but no one seems to sell them anymore." There's a picture of Donald Trump having a piece of steak. I guess the food war, the fight will continue at least for awhile.

TOOBIN: We can only hope.

BLITZER: Gloria, what did you think about that?

BORGER: I think it is silly.

And I think whether it is nicknames you call people, lying Ted, or crooked Hillary, or whatever...

(CROSSTALK)

CHALIAN: One in 38.

BORGER: Yes, exactly. I just think, you know, it is just part of the way the campaign has been, quite honestly.

BLITZER: But, David, the ridicule effort by Trump, it has worked so far. Low-energy Jeb, if you remember. Lying Ted.

(CROSSTALK)

CHALIAN: He knows how to brand.

BLITZER: All right. He brands these guys.

CHALIAN: Better than anyone else I have seen in American politics.

Not only has he branded his opponents really well, he branded himself really well throughout this race. Obviously, it is what brought him to this point.

BORGER: I don't think Kasich is as good at it.

(CROSSTALK)

BLITZER: Hold on.

Kevin, he has done so well with all this branding, ridiculing his opponents, getting nicknames for them. Why not continue until it is done?

MADDEN: Look, he is a substance-free candidate in a substance-free campaign.

As long as that continues, he is perfectly positioned to be the front- runner, at least inside the Republican primary.

But, to David's point, that's what he does best, is he draws caricatures about his opponents. Low-energy Jeb Bush, you couldn't talk to anybody who didn't -- that wasn't the first thing that came to their mind when they thought Jeb Bush after he repeated it over and over. Same with Marco Rubio about his youth.

This will probably happen the same with John Kasich. Again, the big problem for the country is there's zero substance to it.

BLITZER: Let me play this clip, Jeffrey, and I want to get your reaction. Listen to this.

(BEGIN VIDEO CLIP)

TRUMP: Couple of people said presidential. And I gave a sporting analogy. It's like do we want to change at this point? Do we want to change? Do I look like a president? How handsome am I, right? How handsome?

(END VIDEO CLIP)

BLITZER: You're smiling. Go ahead.

TOOBIN: You know, every time he refers to Senator Cruz as Senator Cruz, we think, oh, he has gone presidential. Then three hours later, he's back to lying Ted.

I think he's going with what works. This guy is practically the presumptive nominee of the Republican Party. Why should he change what's working now, which is calling people nicknames?

(CROSSTALK)

BLITZER: Jeffrey, he makes a good point. Right? It has worked so far. It's almost a year. In June, it will be a year he announced he is running for president. He has been almost the front-runner every day since then.

CHALIAN: Yes.

No, I think we have seen him -- I think maybe one of the most impressive parts of his campaign so far is how he has responded after that Wisconsin loss, and bringing on more professionals for this delegate piece of the pie. He understood he needed to change his operation and he changed himself.

He is not doing as many interviews. He's not calling into every morning show. He's not doing Sunday shows. This guy can adapt. I think that's what actually makes him a potential problem for the Democrats in a general election if he doesn't....

(CROSSTALK)

BLITZER: He's giving a major foreign policy speech on Wednesday here in Washington, scripted, teleprompter. It's only the second time, Gloria, he's going to be doing that.

BORGER: It is a different stage of the campaign. You have different people now involved with the campaign who are saying to him you have to put some meat on the bones here. And I think that's what they're trying to do.

I think he has got to walk a fine line, though, because what attracts people to Donald Trump is his authenticity and his bravado and the fact that he tells it like it is. We have seen that in exit poll after exit poll after exit poll.

When you have some people talking about Trump and saying, "Now he's going to change," you know, I heard from the Mitt Romney people after that story came out about maybe Trump is going to start acting differently. And they reminded me about the Etch-a-Sketch line, where a former Romney...

[18:30:15] MADDEN: Probably just bitterness. And by the way, make sure you tell everybody that wasn't me.

BORGER: No, it wasn't you. But remember, back in that campaign, when a Romney aid said it's like an Etch-a-Sketch and where he's going to change for the general. You can't do that with Donald Trump.

BLITZER: Very quickly, all of a sudden, Cruz word out there he's vetting Carly Fiorina, potentially, as his vice-presidential running mate?

MADDEN: Yes. I think one of the things is they're going through the process of thinking, when they get to the convention, what big move or motion can they make to appeal to the delegates. The key for him, after finding the right candidate, is whether or not he can roll that person out with maximum impact. If they were to do it now, there's a long period of space between now and Cleveland where it may not have as big of a pop. But if they get to Cleveland and do it at the right moment, it could send a big message to some of those delegates they're trying to woo, should they ever get to a second ballot.

BLITZER: Is that a good idea, Jeffrey?

TOOBIN: Well, remember, 1976 Richard Schweiker, Ronald Reagan named Richard Schweiker, who was a moderate Republican senator from Pennsylvania, as his nominee for vice president well in advance of the convention as an attempt to show that he was moving towards the center. He came pretty close in the convention. Of course, he lost the nomination to Gerald Ford, but the idea of naming a vice president in advance is something that's been tried before; hasn't worked.

MADDEN: Just not the Twitter age.

BORGER: You know, in -- right. And Jeffrey, you know, in 1976 it backfired because Schweiker was way too moderate. And they tried to force Ford to name a veep, and he wouldn't do it. He would have had to change the rules, and it presaged this whole rules fight. So if you name the vice president, it can also backfire on you. You have to be really careful about it.

BLITZER: All right, guys. Everyone stand by. There's more coming in. Donald Trump, we're standing by to hear from him. He's live in Pennsylvania as he ramps up his attacks on Ted Cruz, John Kasich and their new alliance.

Plus, we're also getting new details about Prince's final days and a medical emergency on his private jet shortly before his death.

(COMMERCIAL BREAK)

[18:36:57] BLITZER: We are following new developments in the race for the Republican presidential nomination on this, the eve of five crucial primaries. Donald Trump is accusing his two rivals of collusion. He's ridiculing Senator Ted Cruz and Governor John Kasich for making a deal to divide some of the upcoming primary states in hopes of winning enough delegates to at least block Trump from this summer's Republican convention.

Joining us now, Trump senior advisor Tana Goertz.

Tana, thanks very much for joining us. How worried is Donald Trump that this deal between Kasich and Cruz will prevent him from securing the nomination on the first round at the convention in Cleveland?

TANA GOERTZ, TRUMP SENIOR ADVISOR: Oh, he's not worried at all, Wolf. We're not worried at the Trump campaign. It's just -- it's Washington, D.C., politics all over again, exactly what Mr. Trump said. It's a corrupt system, and it's unfortunate that these two candidates want to go together for their last hoorah, because they realize that Mr. Trump is unstoppable. So we're not worried.

BLITZER: Because Cruz has said one-on-one, he can beat Trump. And he's putting a lot of his eggs in the Indiana basket right now, Indiana a week from tomorrow. If Cruz wins in Indiana, how much of a setback is that for Trump eventually trying to get 1,237 delegates on the first round?

GOERTZ: Well, I don't like to ever speculate what can't be. That can never happen, so it's never going to happen. I mean, the voters in Indiana are very smart people, and they're going to realize exactly what Governor Kasich and Senator Cruz want to do. And they're smart. They are 100 percent behind Donald Trump and his vision for America. And we will see, one week from tomorrow, Wolf, when you do that key race alert and announce Donald Trump the winner, I can't wait for it.

BLITZER: We'll see if we can make a major projection, as we say, on that night when the polls close in Indiana.

GOERTZ: Yes.

BLITZER: Cruz also, really, is lately going after Trump, really hammering him for, he says, being afraid to do a one-on-one debate in advance of Pennsylvania or in advance of Indiana. When you hear Cruz make those allegations that Trump is scared to debate, what's your reaction?

GOERTZ: I just -- I can't laugh hard enough. That's so funny. Mr. Trump is not afraid of Ted Cruz. I can guarantee you that. I've known him 11 years. He's not afraid of many people. So that is just comical to me, actually. Why would Mr. Trump waste his breath, waste his energy, waste his time on doing a debate with a gentleman who's mathematically completely eliminated from the race?

So I think he needs to pack up his little suitcase and just go on home and do exactly what he told Governor Kasich to do, and that is to get out of the race when he wasn't mathematically going to win this thing. So it's time for him to pack up and go home.

BLITZER: But Tana, he's mathematically eliminated from getting the necessary delegates on the first round. John Kasich is mathematically eliminated from getting enough delegates on the first run.

GOERTZ: Right.

BLITZER: But they're not mathematically eliminated. If Trump doesn't get 1,237 on the first round, it goes to a second round. All -- half of those pledged delegates then become unbound. They can vote for whoever they want. Their hope is they'll vote for Kasich or Cruz, and Trump will lose. When you hear that scenario, what's your reaction?

[18:40:23] My reaction is we're going to get to 1,237, and if, God forbid, we don't, the American people are making it very clear who they want as their next president, and people will get in there.

And if it is a contested convention, which I sure hope it won't be, and I would bet all of my eggs and put it in that basket that we will not have to deal with that, we will take this. And people, the American people will vote for Donald J. Trump. And we will not have anyone else to talk about as president of the United States.

It's just -- they need to go home. They need to quit the race, because Mr. Trump is, you just saw what happened in New York City, New York, and it's going to happen again tomorrow. I can't wait for it. And the American people are speaking, and we're listening.

BLITZER: They also -- they also point to these national polls, not Republican polls, national polls showing Trump is very unpopular with large segments of the American electorate out there. They say if Trump is the Republican nominee, Hillary Clinton, presuming she's the Democratic nominee, will become president of the United States. That's one of the arguments they make. I want to get your reaction to that.

GOERTZ: Well, my reaction, Wolf, would be simple. Mr. Trump hasn't even talked about or touched Hillary Clinton. Let's just get the nominee and then, we'll worry about that, because you haven't seen anything yet. If you want to see -- if you want to see a competition, wait until Mr. Trump is up against Hillary Clinton. He'll do exactly what he did to Bill Clinton, in a one 15-second Instagram video, and people were like, "Bill who? What?"

So I don't think we have anything to worry about. We're trying to get the nomination, and then we'll -- we'll worry about Hillary Clinton, but I -- I do not believe we're going to have any problem in that regard, as well.

BLITZER: Tana Goertz, thanks very much for joining us.

GOERTZ: Thank you. Have a great day.

BLITZER: Thank you. When we come back, we're taking a closer look at what's going on, on the Democratic side, the Democratic contest. Bernie Sanders and Hillary Clinton. There's new developments unfolding. We'll be right back.

(COMMERCIAL BREAK)

[18:47:02] BLITZER: We are back with our political team.

I want to check in on the Democratic presidential race now. Right now, Hillary Clinton facing off against Bernie Sanders in five states tomorrow. But tonight, Donald Trump and his lavish life-style clearly on her mind.

Our senior political correspondent Brianna Keilar is joining us now live from Pennsylvania, one of tomorrow's primary battle grounds.

Brianna, Hillary Clinton seems to be pivoting more and more toward the general election.

BRIANNA KEILAR, CNN SENIOR POLITICAL CORRESPONDENT: Wolf, that's right. She has focused very much today on the Republican frontrunner when she was campaigning in Delaware and also here in Pennsylvania. Bernie Sanders campaigning in Pennsylvania as well. It is the big prize tomorrow night, 189 delegates at stake.

And both these candidates are getting ready for dueling rallies tonight in Philadelphia.

(BEGIN VIDEOTAPE)

KEILAR (voice-over): On the eve of primaries in five states, Hillary Clinton is taking aim at Donald Trump.

HILLARY CLINTON (D), PRESIDENTIAL CANDIDATE: Donald Trump says wages are too high in America and he doesn't support raising the minimum wage. And I have said, come out of those towers named for yourself and actually talk to and listen to people.

KEILAR: Clinton ratcheting up her attacks on the GOP runner at a campaign stop in Delaware.

CLINTON: Don't just fly that big jet in and land it, go make a big speech, and insult everybody you can think of, and then get back on that jet and go back to -- you know, your country clubhouse in Florida or your penthouse in New York.

KEILAR: She's trying to position herself as the unifying alternative to Trump -- releasing an ad called love and kindness.

take a moment to talk about some of the differences between Secretary Clinton and myself. For a start, I am very proud to come before you and tell you I do not have a super PAC.

KEILAR: Trailing considerably in the pledged delegate count, Sanders pushed back on critics who say he can't catch up to Clinton on CNN's "STATE OF THE UNION."

SANDERS: I think we do have a path to victory. I think we have come a very, very long way in the last year and we're going to fight for every last vote until California and the D.C. primary.

KEILAR: As Clinton faces criticism from Sanders, she's getting consideration from an unlikely place, conservative mega donor and billionaire, Charles Koch. He said Sunday it's possible Clinton could be better than the GOP nominee.

CHARLES KOCH, CHAIRMAN, KOCH INDUSTRIES: We would have to believe her actions would be quite different than her rhetoric, let me put it that way. But on some of the Republican candidates, before we could support them, we'd have to believe their actions would be quite different from the rhetoric we've heard so far.

[18:50:03] KEILAR: But Clinton was quick to respond, tweeting, "Not interested in endorsements from people who deny climate science and try to make it harder for people to vote."

(END VIDEOTAPE)

KEILAR: And, Wolf, you can see things are heating up here at Hillary Clinton's rally before she gets here, "The New York Times" has been reporting that her campaign is getting ready for veep stakes, that they are building a list of about 15 or 20 potential running mates.

One of them being Ohio Senator Sherrod Brown. This is pretty interesting, Wolf. He just told our Manu Raju a short time ago that he's not interested. He said "I've made it clear I don't really want this job."

BLITZER: All right. Brianna, thank you. Brianna Keilar reporting.

Meanwhile, another major story we're following. A significant increase in the U.S. military presence on the ground in Syria. Hundreds more Special Operations Forces will be heading their soon to help in the fight against ISIS.

Our Pentagon correspondent Barbara Starr reports.

(BEGIN VIDEOTAPE)

BARBARA STARR, CNN PENTAGON CORRESPONDENT (voice-over): To get to ISIS fighters like these seen in a recent propaganda video, President Obama is sending 250 additional U.S. troops into Syria, most special operations forces. The president says the U.S. troops will not have a combat mission. BARACK OBAMA, PRESIDENT OF THE UNITED STATES: They're not going to be

leading the fight on the ground but they will be essential in providing the training and assisting local forces they continue to drive ISIL back.

STARR: The additional 250 troops will join 50 already there. And it will be dangerous. Military medical personnel are also deploying.

BEN RHODES, DEPUTY NATIONAL SECURITY ADVISER: Any Special Forces troops that we deploy into Iraq or Syria are going to be combat- equipped troops. They may be in circumstances where they find themselves in harm's way because these are dangerous places.

STARR: But the president has accepted the Pentagon's recommendation that it's worth the risk.

OBAMA: Their expertise has been critical as local forces have driven ISIL out of key areas.

STARR: The goal now, Raqqah, ISIS' self-declared capital, the center of its so-called caliphate. The special operations forces will try to bring more Sunni Arab fighters into the mix who would be willing to help fight to get Raqqah back. The U.S. will train Arabs and Kurds to spot targets for coalition air strikes. It will also accompany them onto the battlefield to offer real-time advice, but not go all the way to the front lines.

And they will be able to gather critical intelligence, something James Clapper, the director of national intelligence, welcomes.

JAMES CLAPPER, DIRECTOR OF NATIONAL INTELLIGENCE: Any time you get ears and eyes on the ground, that's a good thing.

(END VIDEOTAPE)

STARR: And in Iraq, the U.S. also getting ready to send in another 200 military advisors closer to the front lines -- Wolf.

BLITZER: All right, Barbara, thank you.

Just ahead, a medical emergency forcing an emergency landing. We're learning new details of Prince's final days.

(COMMERCIAL BREAK)

[18:57:33] BLITZER: Tonight, new information on the mystery surrounding the death of Prince as fans await the results of his autopsy and mourn for the music legend. We're learning more about an incident on Prince's private plane about a week before he died at the age of 57.

Brian Todd is here. He's got the latest on the investigation.

There was this medical emergency. What do we know about that?

BRIAN TODD, CNN CORRESPONDENT: Wolf, what we've learned tonight is that this incident just six days before Prince's death had a frightening similarity to his final hours. On April 15th, a private plane carrying Prince from Atlanta back to his home in Minnesota, it had to make an emergency landing at that airport you see there, the Quad City International Airport in Moline, Illinois. Communications just released today by the FAA say the emergency was due to an unresponsive person on board that jet.

Here's what it sounded like when the controllers were speaking to each other and to the pilot.

(BEGIN AUDIO CLIP)

CONTROLLER 1: What's the nature of the emergency? What's the nature of the medical condition?

CONROLLER 2: An unresponsive passenger.

CONTROLLER 2: Jetspeed 990, was it a male or female?

PILOT: It's a male passenger.

(END AUDIO CLIP)

TODD: Now, there are strong indications that Prince was that male passenger. We do know he was rushed to the hospital after an emergency landing at that airport the same day. He was later released from the hospital and returned home to Minnesota.

What we don't know is what happened on the plane or who was on the aircraft with him. We have pressed investigators on those questions. So far, they have not answered them, Wolf.

BLITZER: There are also questions about whether or not he was on medications, right?

TODD: Key questions tonight, Wolf. Specifically, was he on pain medications? We do know that in Atlanta when he was giving those final concert there, Prince carried a cane with him, he was known to have suffered from a bad hip.

We know from friends that he had a very healthy life-style, he was a vegan. But even with all that, we've had a prominent pain management doctor tell us that if someone is taking strong pain medications and is either not used to them or overmedicates, they can lapse into unresponsiveness, even stop breathing. We have not confirmed if Prince was on pain meds and investigators have so far said they could not confirm that. But that is a key threat of this investigation tonight, Wolf, was he on pain medications and could those have contributed to his death?

BLITZER: Any indication of when they will release the results of the autopsy?

TODD: The autopsy results are not can be released for about four weeks. That's another frustrating part. We'll be able to tell what was in his bloodstream, what was in some of his body tissue from that autopsy report, Wolf. But we are not going to know that for at least three and a half to four weeks.

BLITZER: All right. Lots of questions still unanswered. Thanks very much, Brian Todd, for that.